The Winchester SX4 Cantilever Buck is a semi-automatic shotgun in 20 GA with a 22-inch barrel. The cantilever rib is integrated into the barrel and extends over the receiver, giving a stable base for a scope or red dot without needing a separate receiver mount. The receiver is aluminum alloy, the stock is synthetic, and the Invector Plus choke system is included. 
 

Key Specifications 

• UPC: 048702010125 
• Gauge: 20 GA 
• Action: Semi-Automatic 
• Capacity: 3 Rounds 
• Barrel Length: 22 inches 
• Overall Length: 43 inches 
• Weight: 8.5 lbs (136 ounces) 
• Finish: Black Synthetic Stock 
   

Features 

 
The Inflex Technology recoil pad deflects the stock slightly downward as it compresses, which reduces muzzle rise during cycling and keeps the cheek weld more consistent for follow-up shots. The fiber optic front sight and adjustable rear sight work for iron-sight shooting; the cantilever rib handles optic use. The SX4 gas system adjusts to different load pressures, which generally means reliable cycling across a range of 20 GA loads.

The Winchester SX4 Cantilever Buck in 20 GA has a largely positive user base, with a few recurring sticking points.

Reliability is the most-cited strength. Owners report that the shotgun cycles consistently across different loads, including lighter target shells and heavier hunting loads, without adjustments. The 20 GA chambering keeps recoil manageable, which comes up often from newer shooters and those who run the gun for long sessions.

The cantilever design draws specific praise from deer hunters. It lets you mount a scope or red dot directly to the barrel, maintaining zero when you swap barrels, which is useful if you run different configurations for different seasons.

On the negative side: price is the most common complaint, with some buyers feeling the SX4 costs more than comparable semi-autos. A few owners mention a break-in period during the first 50-100 rounds before cycling becomes fully reliable. Weight distribution gets occasional mention. At 8.5 lbs the gun is on the heavier side for a 20 GA, and some find it slightly muzzle-heavy during extended carry. Aftermarket accessories specific to this model are also limited compared to Mossberg or Remington platforms.